Method of making lock nuts



June 18, 1935.

I. c. EMERY METHOD OF MAKING LOCK NUTS 2 Sheets-Sheet 1 Filed Nov. 21, .1952

June 1935;; c. EMERY 2,005,651 METHOD OF MAKING LOCK NUTS I F-iledNov. 21, 1932' 2 Sheets-Sheet 2 Patented June 18, 1935 I. C. Emermfialtimore, MIL, assignor to TheLock Nut Corporation of America, Chicago, Ill.,' a

corporation of Delaware Application November 21, 1932,.iSerialNo. 643,759

The present invention relates to a'rnethod of making lock nuts of the type having superposed wings joinedbya neck. i

zLock. nuts of this generaltype are well-known in the art and several processes? have been devised for making the same; One is claimed in my Patent l,5l6,72l"-granted November 25, 1-924. Largenumbers of lock nuts have been made by this'patented process, and'the nuts themselves; so .far- -a's thelocking feature is concerned, are considered-very satisfactory'and desirable. How'- everflthe nuts werenot bought in quantities anywhere near sufficient to supply the extensive market therefor, due to the iactthat the cost of zmanu'facture by this process wasgreater than desired. I I

1Itis=one of the main objects of the presentinvention to provide a processwhereby, when-the lock-nuts are made insubstantial quantitiesthey canbe-manufactured at a cost only slightly exceedingthe cost of making ordinary nuts.

The' loek nuts made by my prior processhad rounded edges at the outside of the neck. Al-' though this did'.not-'afiectthe strength or looking qualities of the nut, yet there were somewh'o objected on account of appearance. 'If suificient pressures we'reemployed, the outside surface of the neck could be squared up, but the cost of supplying the required high pressures' was 'so great that, as stated, the lock nuts were left with the rounded edges. Again, it was necessary to make the nut from a blank having the grain running lengthwise thereof. In view of the methd of making the nut, the stock or metal had'to beselected very carefully, and even with selectedstock, oftentimes the metal of the neck portion was strained or slightly cracked, and in any event was weakened because of being worked cold. Furthermore, the neck was'too thin. Attempts in my prior process before the bending step, but this was not successful, since the bending deformed the shape of the holes. Hence in my priorprocess it was necessaryv toform the holes after the bending. operation Even then these holes could not be punched .for various reasons and had to be drilled.

.It is another object of the present invention to overcome all of these defects. I

' Other objects and features of novelty will be apparent from the descriptiontake'n inconnection withthe drawings, in which j v Figure 1 is a perspective view of the front end of'a strip of blanks from which'the nuts are were made to punch theholesin the blank used- Figure 2 isa similar perspective view, showing the condition of the first blank after the first step of the process;

Figure 3 shows the blank after the narrow strip midway between the holes, or what may be "I termed the neck portion, has been heated;

Figure 4 is a diagrammatic elevational View, showing the blank in a dieand after the plunger has bent the-two wings of the nut about the heated portion;

Figure5 is a view similar toFig. 4, showing the plunger at'the bottom of its stroke and after having squared up the outer surface of the neck and-thickened the same; l

Figure 6 is a perspective view of a. lock nut after it"has been ejected from the -machine-of Fig. 5;

Figure 7 is a sectional elevation of the nut of Fig. 6 after the-samehas been tapped orthreaded;

Figure 8 is a similar view after the two wings have been'pressed towardeach other slightly;

Figure 9 is a diagrammatic elevational view, illustrating some of the instrumentalities used to make nuts accordingto the presentprocess;

Figure 10 is a sectional elevation taken substantiallyon the line Iii-4'0 of Fig. 9;

Figure ll-is an elevational view-of a bent-blank similar to that shown in Fig. 4 but made froma blankthat has-no groove or thinned portion; and

Figure '12, is a'similar-view, illustrating the bent blank made from ablank'having a groove but no projecting ridge 7 like 24.

Lock nuts made by the present process are formedfrom sections of a long strip of metal rolledto a thickness the same as the wings of the nuts. The front endof suchastrip is shown in Fig. l, theportion used to make one nut being I the metal between the dotted 1ine'20 and'thefront end of the strip.

The first-step of theprocess consists in"forIn'-,

ing the holesZl, one in the center of each-wing 25 and 26. Preferably this is done *by'punching. For reasons explained'hereinafter, itis desirable to thin the metal of the blank throughout a nar row'stripex'tending transversely of the blank and PATENT OFFICE surface of the neck of the nut. After the wings of the nut have been bent about the neck as a hinge, it is found that the metal at the neck usually is not thick enough or entirely properly disposed. To offset this, the bottom of the blank may be formed with a projecting strip 24 parallel with the groove 23. The groove and projecting strip are of such size as to leave the proper amount v the holes. Thus, as shown in Fig. 3, the neck 'portion 22'is heated and as far as possible the heating is confined to the neck. This is done by raising the temperature of the neck as rapidly as possible so' that the heat cannot diffuse away through the metal. Perhaps this may be. effected most easily electrically. Thus an electric conductor in contact with the ridge 24 and a reciprocating conductor above, the blank may be employed, the latter being moved down into the groove'and contacting .with the bottom surface thereof. Of

course both of the conductors would besuitably insulated. The neck is heated to, such temperature that the wings can be bent easily around the neck as a'hinge. The necks of nuts made by my prior process, where the bending was effected cold, were weakened because the metal was subjected to stresses greater than its elastic limit. Hence cracks and imperfections developed. With the present process, however, where the bending is effected with the-neck heated to the proper temperaturathe metal is not stressed beyond its elastic limit and hence no imperfections develop.

On the contrary, the bending of the metal hot and the subsequent step of flattening theouter surface of the neck of the'blank and squaring up the entire blank, works the .metal in the neck and. really improves its quality.-

After the neck portion of the blank hasbeen heated, the wings. are turned downwardly, as viewed in Fig. 3, about the heated portion as a hinge to positions that are substantially parallel.

The form of a blank near the end of this bending operation is shown in Fig. 4. As previously pointed out, it will benoted that the outer surface of the neck is substantially flat because the flat sides of the groove 23 really in effect preformed the flat outer surface of the neck after bending. The slight projection 42 is purposely provided so that the projection may be forced downwardly to thicken. the neck in the next operation.

After bending the wings into the position shown 'in Fig.4, the outside surface of the neck of the blank is smoothed and flattened, and the neck itself thickened. 'At the same time the entire blank is squared up so that the holes are in alignment.

Theblank as ejected from the machine of Fig. 5 isshown in perspective in Fig. 6.

The blank is now threadedor tapped, giving the nut shown in Fig. 7. a

Finally the two wings 25 and 26 are pressed slightly out of parallel to throw the threads of the two wings slightly out of position so that when the nut is screwed on abolt the nut will be held against turning movement in a well-known manner. V

According to the present invention, the process is continuous, the blanks being moved from station to station and finally ejected in the form shown by Fig. 6. Thus referring to Fig. 9, there i is there shown a die 21 along the top surface of which is fed the strip of blanks'B from station to station or step by step. At the first station indicated by the dotted line 28, a head 29 having the punches 30 moves downwardly and forms the holes 2| in the blank. Where the metal of the neck 22 is to be thinned, the punch can be provided with the transverse pressure member 3|, which will form the fiat-sided groove 23 at the same time thatthe holes are punched. If it is desired to have the blank formed with the transverse strip 24, then the die 21 is provided with a slight depression 32 of proper shape to form this strip. Obviously the holes will be punched and the groove 23 and strip 24 formed simultaneously.

After this punching operation, the blank is fed along the top of the die 21 so that it now occupies the position indicated by the dotted line 33, -a new blank being presented to the punch 29. In posi tion 33,. a narrow transverse strip of the blankis heated. For thispurposethere are provided the electrical conducting members 34 and 35, both properly insulated and 35 being mounted for vertical reciprocation. Where the blank has a been on the proper length of time and the nar-v g row strip rapidly heated to the desired temperature, the conductor is moved upwardly and the blank advanced to the position indicated by the dotted line 36. Here a plunger 31 having a right angle edge 38 descends and the edge cuts off the blank 36 alongthe line 39, forcing the two wings of the blank downwardly into the recess 40 of the die. The neck or central transverse strip of the blank is supported on the upper surface of the narrow supporting strip 4| during this bend-. ing operation. After the plunger 31 has descended to near the bottom of its stroke, the blank will take the shape shown in Fig. 4, both wings having been bent about theneck while hot into substantially parallel positions. 1

If a blank is employed that has no thinned portion or groove, after the bending operation the appearance of the same will be as illustrated in Fig. 11. It will be noted that the thickness of the neck is the same as the thickness of the wings. Such bent blank can be squared up and the outer surface of the neck flattened by the, operation illustrated by Fig. 5, but obviously it requires more work to do this than when a blank like that shown in Fig. 3 is employed.

Again, instead of a blank like that shown in up the nut where this amount of projecting metal;v

is present.

If the groove 23 and projecting ridge 24 are.

properly made, as shown inFig. 3, there is only a very slight amount of the projecting metal 42 at the center of the outer'surface of the neck. Hence very little work on the metal is required to square up the nut and flatten the outer sur-, face of the neck. Furthermore, the projecting metal 42 'is desired because in. thenext step it is forced into position soas to thicken the neck.

. Inbending the wings around the top edge'4l of the support it is necessarythatxthe top ,edge M be: substantially flush withthe top surface of the dieand so positioned that the ends 42 and 45 of the wings will not be prevented from being forced into the positions shown by Fig. by touching the bottom surface 46 of the die recess 49. With the edge 4 I of the support in this proper position for bending the wings to nearlyfinal position, it is found that there is not sufficient metal for the required strength at the neck of thenut. Further more,in the operation shown by Fig. 5,when the plunger 31 moves to its bottom position, the surface 41 of the plunger in flattening the outside surface of the neck of the nut would decrease the thickness of the neck. In order to overcome this defect and increase the'thickness of the neck as compared to priornuts of this type, the support is mounted for lateral sliding motion, as shown in Fig.10. Thus if the support 48 is moved to the left so that the edge thereof substantially contacts with" the surface 50, then the supporting edge 5| will be brought under the plunger 3'! and this edge will be somewhat spaced from the inner surface of the neck, as shown in Fig. 5. Of course the effect of withdrawing the supporting edge 4i could be'obtain'edin other ways.

. When the plunger moves from the position of Fig. 4 to that of Fig. 5, it putspressure on the whole blank, thereby squaring up the blank and smoothingand flattening the outer surface of the neck. Furthermore, the projecting metal 42 w is forced downwardly to thicken the neck portion.

As the ends 44 and 45 of the wings rest on the bottom of the die and are forced thereagainst, both wings are properly positioned and as a result the holes 2| will beproperly aligned.

When the plunger 37 is raised, the nut blank will stick in the recess of the plunger until it reaches its upper position, when it can be removed by a sidewise moving ejector.

While the nut blank is being bent into the form shown in Figs. 4 and 5, the metal at the neck, being hot, is being worked by the plunger, but the heat is dissipated through the blank into the plunger and by contact of the plunger with the heated neck portion. This cooling action is sufficiently rapid so that the portion of the metal at the neck is hardened, thereby increasing the strength and desirability of the final product.

It does not make any difference which waythe grain runs in the blank fed to the machine for forming the nut, as the neck portion that is bent is heated and the bending is eifected while theneck is hot. Where the bending is done while the neck is at an ordinary temperature, as taught by my prior patent, it has been found absolutely necessary to have the grain run lengthwise of the blank. In view of the fact that it is immaterial which way the grain runs in the blank, the strip of blanks can be made of a width as shown in Figs. 1, 2 and 3, or having a width equal to the dimension line 28 of Fig. 9. In the latter case the blanks would be fed through the dies in such manner that the bend would be made parallel with the grain of the blank.

Instead of forming the thinned transverse strip midway between the holes of the blank by the presser member 3| etc., this could be done in the mill rolling the strips of blanks, so that the blank as fed into the machine of Fig. 9 would have the thinned section already formed.

Although the invention has been described in connection .with forming a square nut, it is obvious that by suitably stamping or cutting the outline of the blank that hexagonal nuts could be inade'ornuts ofzother shapes. i 1

It will be understood that where mention is made of heating the neck electrically that the conductors are in circuit with a supply of low voltage electricity and that the neck will be brought to therequired temperature in a manner similar to spot welding.

Although one method of carrying out myinvention has been described in detail, it is to be understood that it is not limited to the specific details, but includes modifications and changes which come within the scope of the appended claims. T

Having thus described the invention, what is claimed as new and desired to be secured by Letters Patent is: I

1'. In the process of making metal lock nuts of the type having superposed wings joined by a neck, the steps of forming two holes in a flat blank, one in the center of each of the subsequently formed wings, forming a transverse groove in one face of the blank between said holes, heating the metal at the bottom of the groove, bending the 'two wings away'from thegroove and toward each other into spaced relation;

made into a plurality of lock nuts of the type having superposed wings joined by a neck, ad-

vancing said strip station by station, and performing on a section of the same sufficient to make a nut the following steps: one, while at the first station forming two holes in the strip, one in the center of each of the subsequently formed wings; two, while at the second station heating a narrow transverse strip of the blank substantially midway between said holes; three, while at the third station cutting off said section and bending the two like parts of the section about the heated part as a hinge to form the spaced wings connected by a neck.

3. The process according to claim 2 wherein the long strip is formed by rolling.

l. The process according to claim 2 wherein the step numbered one includes forming a narrow transverse groove midway between the holes.

5. The process according to claim 2 wherein the step numbered one includes forming a narrow transverse groove midway between the holes, said groove having flat sides substantially perpendicular to the face of the blank.

6. The process according to claim 2 wherein the step numbered one also includes forming a narrow transverse groove midway between the holes and a transverse rib parallel to the groove on the other face of the blank.

'7. The process according to claim 2 wherein the step numbered three also includes applying pressure to the outside surface of the neck to flatten the same and square up the blank.

8. The process according to claim 2 wherein Y the step numbered three also includes rapidly cooling the neck to harden the same.

9. In the process of making nuts of the type having superposed wings joined by a neck, the steps of forming a long narrow strip with transverse grooves spaced equal to the length of a blank that will form a nut, forming two holes symmetrically located,.one on each side of a groove, heating the neck of metal adjacent the groove, severing the strip midway between adjacent grooves, and bending the severed portion about said neck as a hinge while hot to position the two wings in substantially parallel. spaced relation.

; 10. The process according to claim 9 wherein the grooves have flat sides substantially perpendicular to the face of the strip.

11. The process according to claim 9 with the added step of applying pressure to the outside of theneck to flatten the. same and square up i the blank.

12. The process according to claim 9 with the added step of applying pressure to the outside of the neck while the blank is in a die to flatten and thicken said neck and square up the blank.

13. In the process of making lock nuts of the type having superposed wings joined by a neck, the steps of forming two holes in a flat blank, one in the center of each of the subsequently formed wings, pressing a narrow transverse strip of the blank midway between the holes to thin the blank at this region, heating said strip, and bending the blank about said strip as a hinge while the strip remains hot, thereby forming spaced wings connected by a neck.

14. In the process of making metal locknuts of the type having superposed wings joined by a neck, the steps of forming two holes in a fiat blank, one in the center of each of the subsequently formed wings, heating a narrow transverse strip or the blank substantially midway 15. In the process of making lock nuts of the type having superposed wings joined by a neck,

the steps of forming two holes in a flat blank, one in the center of each of thesubsequently formed wings, forming a narrow transverse groove midwaybetween the holes and also, a

transverse rib parallel to the groove on theother face of the blank, heating the narrow transverse strip of metal at the bottom of said groove, and bending the blank about said heated strip as, a hinge while said strip is hot, thereby forming spaced wings connected by a neck.

16. The process according to claim 15 wherein said groove is formed with flat sides substantially perpendicular to the face of the blank.

17. The process of making nuts of the type having superposed wings joined by a neck consisting in taking a flat blank consisting of two like wings of uniform thickness connected by a narrow thinner neck, each wing having a centrally located hole therethrough, heating thethin neck portion, bending the, blank about said neck as a hinge while the neck remains hot, and applying pressure to the outside of the neck to increase the thickness thereof and square up the 

